A sociopathic gunman’s insanity defense failed on Thursday when a Queens jury convicted him of shooting three men dead — two on the Q111 bus.

“Oh thank God!” said a relative of 18-year-old Keith Murrell who was Damel Burton’s first victim on Dec. 2, 2011.

Burton, 36, was quickly found guilty for the murders of Murrell and Marvin Gilkes, 36, as well as the attempted murder of Jojuan Lipsey, 31.

The admitted “author and architect” of the shootings told authorities he was protecting himself from people conspiring to follow him since he was released from prison in 2010.

Burton’s attorney, Anthony Rattoballi, attempted to sway the juror of his client’s mental defect with medical records from Bellevue Hospital, Riker’s Island and two court-appointed doctor’s that all diagnosis the killer with delusional paranoia, to no avail.

“We did not feel he mentally fit the legal factor of insanity,” said one juror after they deliberated for almost three hours.

Prosecutor, Daniel Saunders proved Burton did not suffer from paranoid delusional schizophrenia, but rather has an anti-social personality disorder and just “does not give a damn” about his actions and was a “high on cocaine.”

“The shootings on the bus was definitely cold-blooded murder and shooting the kid was definitely revenge, nothing more, nothing less,” said another juror.

Burton went on a 48-hour cocaine binge before he shot Murrell — his longtime girlfriend’s son — in the chest inside their Foch Blvd apartment and calmly hopped on the Q111 bus.

The failing Everest University student fired one bullet in the back of an unsuspected Gilkes’ head with a .9 mm semi-automatic he concealed inside his jacket pocket.

He fired another shot that hit Lipsey in the face and left him permanently disabled.

Burton didn’t flee the scene and was captured by police minutes later standing in 40 feet from a marked patrol car.

While in custody, Burton also came clean about shooting a man in Brooklyn nine days before the shooting using the same murder weapon. Despite the victim’s lack of cooperation, the case is still pending.

Burton faces more than 75 years to life in prison when sentenced by Queens Supreme Court Justice Richard Buchter later this month.